Eliminate polling of overlay decoration dimensions

And remove pollDOM method entirely.

Signed-off-by: Max Brunsfeld <maxbrunsfeld@github.com>

src/overlay-manager.coffee

@@ -1,3 +1,5 @@
+elementResizeDetector = require('element-resize-detector')({strategy: 'scroll'})
+
 module.exports =
 class OverlayManager
   constructor: (@presenter, @container, @views) ->
@@ -12,6 +14,7 @@ class OverlayManager
       unless state.content.overlays.hasOwnProperty(id)
         delete @overlaysById[id]
         overlayNode.remove()
+        elementResizeDetector.uninstall(overlayNode)
 
   shouldUpdateOverlay: (decorationId, overlay) ->
     cachedOverlay = @overlaysById[decorationId]
@@ -19,10 +22,6 @@ class OverlayManager
     cachedOverlay.pixelPosition?.top isnt overlay.pixelPosition?.top or
       cachedOverlay.pixelPosition?.left isnt overlay.pixelPosition?.left
 
-  measureOverlays: ->
-    for decorationId, {itemView} of @overlaysById
-      @measureOverlay(decorationId, itemView)
-
   measureOverlay: (decorationId, itemView) ->
     contentMargin = parseInt(getComputedStyle(itemView)['margin-left']) ? 0
     @presenter.setOverlayDimensions(decorationId, itemView.offsetWidth, itemView.offsetHeight, contentMargin)
@@ -33,13 +32,19 @@ class OverlayManager
     unless overlayNode = cachedOverlay?.overlayNode
       overlayNode = document.createElement('atom-overlay')
       overlayNode.classList.add(klass) if klass?
+      elementResizeDetector.listenTo(overlayNode, =>
+        if overlayNode.parentElement?
+          @measureOverlay(decorationId, itemView)
+      )
       @container.appendChild(overlayNode)
       @overlaysById[decorationId] = cachedOverlay = {overlayNode, itemView}
 
     # The same node may be used in more than one overlay. This steals the node
     # back if it has been displayed in another overlay.
-    overlayNode.appendChild(itemView) if overlayNode.childNodes.length is 0
+    overlayNode.appendChild(itemView) unless overlayNode.contains(itemView)
 
     cachedOverlay.pixelPosition = pixelPosition
     overlayNode.style.top = pixelPosition.top + 'px'
     overlayNode.style.left = pixelPosition.left + 'px'
+
+    @measureOverlay(decorationId, itemView)

src/text-editor-component.coffee

@@ -106,8 +106,6 @@ class TextEditorComponent
       @disposables.add @themes.onDidChangeActiveThemes @onAllThemesLoaded
     @disposables.add scrollbarStyle.onDidChangePreferredScrollbarStyle @refreshScrollbars
 
-    @disposables.add @views.pollDocument(@pollDOM)
-
     @updateSync()
     @initialized = true
 
@@ -204,7 +202,6 @@ class TextEditorComponent
     @linesComponent.updateSync(@presenter.getPreMeasurementState())
 
   readAfterUpdateSync: =>
-    @overlayManager?.measureOverlays()
     @linesComponent.measureBlockDecorations()
     @offScreenBlockDecorationsComponent.measureBlockDecorations()
 
@@ -753,10 +750,6 @@ class TextEditorComponent
 
     @domNode? and (@domNode.offsetHeight > 0 or @domNode.offsetWidth > 0)
 
-  pollDOM: =>
-    if @isVisible()
-      @overlayManager?.measureOverlays()
-
   # Measure explicitly-styled height and width and relay them to the model. If
   # these values aren't explicitly styled, we assume the editor is unconstrained
   # and use the scrollHeight / scrollWidth as its height and width in